Work-clamp for sewing-machines.



PATENTED MAY 2, 1905.

G. S. G ATCHELL. v WORK CLAMP FOR SEWING MACHINES.

APPLIOATiON FILED APR. 26, 1904.

l/v-i/limcmao UNITED STATES Patented May 2, 1905.

PATENT OFFICE.

GEORGE S. GATOHELL, OF ELIZABETH, NEW JERSEY, ASSIGNOR TO THE SINGER MANUFACTURING COMPANY, A CORPORATION OF NEW JERSEY.

WORK-CLAMP "FOR SEWING-MACHINES.

SPECIFICATION forming part of Letters Patent N0. 789,126, dated May 2, 1905.

Application filed April 26, 1904. Serial No. 204,945.

To all whom, it may concern.-

Be it known that I, GEORGE S. GA'roHELL, a citizen of the United States, residing at Elizabeth, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Work-Clamps for Sewing-Machines, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention has for its object to provide a simple and effective form of workclamp capable when closed upon the material of stretching the latter for the stitching operation; and it consists, essentially, in the combination, with, the usual spring-pressed clamping-lever, of a foot comprising two clamping-jaws, each provided at opposite ends with lateral ears, and common pivotal connections intermediate said clamp-lever and the lateral ears of said jaws. The pivotal connections of. the clamping-jaws with the lever by which they are carried are preferably laterally adjustable in order to permit the jaws to be lined up with the stitchforming mechanism and the positions'and direction of motion of the work feeding and shifting slides by which the clamp is carried.

In work-clamps for buttonhole-machines heretofore unprovided with special means for spreading the jaws when closed upon the goods, so as to stretch the latter for the stitching operation, in certain instancesthe jaws have been attached to their carriers in such manner as to yield laterally when forced upon the material owing to their outward inclination in respect of the direction of opening and closing movement of the clamp. As it has been necessary to engage the material comparatively close to the stitching-line, the divergence of the jaws has necessarily been so slight as to require a considerable pressure, and therefore to involve the use of a strong clamp-spring to effect the requisite stretching of the material. This was objectionable for two reasons. First, because the excessive pressure upon the clamp-jaws produced deep mdentatlons n the material, and therefore marred its appearance, and, second,

ment to the clamping-jaws, I am enabled by,

simple means and with little effort on the part of the operator to secure as effective operation of the clamp in holding and stretching the material as has been heretofore attained by means of separate and independent holdiing and clamping devices for the work in I'buttonhole-machines of different types.

By providing the clamping-jaws with offset common pivotal connections not only are the jaws adapted to insure compensation j in the pressure upon the work when the thickness of the material is variable, but the initial engagement of the operative edges of the jaws with the work when the clamp is closed upon the latter affords a resistance whereby such-work-engaging edges are constituted movable fulcra about which the common offset pivot moves toward the work, thereby forcing such edges apart and with them the adjacent material of which the intermediate portion is thus drawn taut across the throat-plate.

The invention will be understood by reference to the drawings annexed, in which- Figure 1 is a plan of a clamping-foot embodying the present invention with the adjacent portion of the clamp-lever. Fig. 2 is a side elevation of the same with the cooperating clamp-slide represented in section. Figs. 3 and 4 are end elevations of the clamp, showing the latter in open and closed positions, with the material interposed between the jaws and the clamp-plate constituting the lower member of the clamp. Figs. 5 and 6 are perspective views, respectively, of one of the clamping-jaws and one of the pivotingbrackets by which the same is secured to the clamping-lever. Fig. 7 is an end elevation similar to Fig. 4, but showing the relative positions of the opposed clamping-j aws when engaging material of uneven thickness.

' I have shown the present improvement embodied in a work-clamp designed for application in the buttonhole cutting and stitching machine disclosed in the a plication of E. B. Allen, filed April 21, 1904, erial No. 204,160, the general construction and mode of operation of the clamp being substantially the same as the primary clamp therein shown and described, excepting in the construction of the foot of the latter.

The clamp-lever 1 is shown provided with forked forward end, to the extremities of which is connected, by means of the fastening-screws 2, a flat carrying plate or carrier 3, having a central rectangular opening 4 for the passage of the cutting-knife and needle and provided at the ends with the transverse slots 5, to which are loosely fitted the rectangular bosses 6, formed upon the base of the bracket 7 and adjustably secured to the plate 3 by means of fastening-screws 8. Each of the clamping-jaws consists of a flat bar 9, with perforated lateral ears 10, the lower edge of one of each and that of the bar 9 being serrated to insure the firm hold of the jaw upon the material when forced upon the same by the clamp-lever 1. The lateral ears 10 are provided with pivot-holes 11, and when the ears of the opposed clamping-jaws at corresponding ends are inserted between the perforated lugs of the bracket 7 they are pivoted together and to such bracket by means of the common pivot-screws 12. Each of the jaws 9 is pressed normally downward by means of 1 the flat spring 13, secured to the under side of the plate 3 by the screws 14, the end of one of the cars 10 upon each clamp-j aw 9 offering a shoulder 15 for engagement with the other clamp-j aw to limit the closing movement of the jaws under the action of their respective springs 13.

In the use of the clamp as above described the clamp-lever 1 is raised from the slideplate 16 in opposition to its spring by the usual means and the material 17 introduced, the jaws 9 thus asssuming the position represented in Fig. 3, with the shoulder 15 of the lug 10 carried by each jaw 9 in engagement with the inner face of the other jaw under the action of the spring 13. Upon the depression of the clamp-lever 1, and consequent engagement of the serrated edges of the jaws 9 with the material, the ears 10, in conjunction with the pivotal pins 12, produce a wedging action between the jaws, which tends to force them apart to stretch the material intermediate their work-engaging edges, one or both of the upper edges of the jaws becoming seated against the plate 3 or interposed springs 13. As the operative or work-engaging edges of the jaws 9 are disposed upon opposite sides of the line of stitching (indi- "material upon which it is clamped.

. figure referred to-it will be observed that the cated in the drawings by the longitudinal slot in the throat-plate) and as such edges are parallel and equal in length, their action upon the material is to stretch the intermediate portion thereof uniformly throughout the length of buttonhole, which is evidently essential to the production of a perfect buttonhole.

As indicated in Fig. 7, the present clamping-foot possesses material advantages over others heretofore in use in that its action is uniform, regardless of the character of the In the material under the two jaws varies materially in thickness; but as the application of pressure. imposed by the clamp-lever 1 is always upon the pivot-screws 12 midway between the jaws 9 it is evident that the pressure imposed by each jaw is substantially the same.

The present improvement possesses the advantage of adjustability to place the clamping-jaws in the proper relation with the stitch-forming devices and the clamp-carrying slides in that the bosses 6 are adjustable transversely in their respective slots in the carrying-plate 3, whereby the brackets 7' i may be shifted equally in the same direction to move the jaws 9 bodily in such direction, or may be shifted unequally in the same or opposite directions within certain limits for changing either or both the angular and bodily relation of the jaws 9 in respect of the stitch-forming devices and other cooperating parts of the machine.

As the clamp-lever 1 and plate 3 compose the carrying member, to which the jaws 9 are secured by the common pivotal connection ,disposed in the plane of the needle-opening Land knife-slot in the throat-plate, and thus in the line of the buttonhole-slit, itis evident that such component parts of the jaw-carry- 'ing member are not necessarily constructed 1 separately and secured together by the fas- Etening-screws 2, as herein shown and described. In order that the point of application of the clamping pressure imposedby the lever 1 maybe located in the proper'positionto enable the jaws to operate as described in stretching the material to be stitched, it is essential that. the common pivotal connection between the jaws and such carrying member be disposed intermediate the workengaging serrated edges of'the jaws and sub stantially midway between such jaws, and thus in the plane of the center of the needle-opening of the throat-plate, as indicated in the drawings. In the operation of the clamp the serrated work-engaging edges of the same thus constitute relatively receding centers, about which the laterally-offset pivotal connections formed by the pins 12 revolve, which in turn intheir movement toward the work force the jaws apart to produce the stretching of the material, as above described.

By the term common pivotal connection as employed herein to designate the means whereby the work-engaging jaws are secured to their carrier is to be understood pivotal connections upon a common axial line, the same pivotal pin extending not necessarily continuously through both of the in dependently-moving clamp-jaws at each end of the carrier.

Having thus set forth the nature of my invention, what I claim herein is 1. A work clamp for sewing machines comprising a carrier, clamp-jaws each movable independently of the other and provided at opposite ends with lateral ears, and common pivotal connections intermediate said carrier and the lateral ears of said jaws.

2. A work clamp for sewing machines comprising a carrier, independent clampjaws each provided at opposite ends with lateral ears, and common pivotal connections intermediate said carrier and the lateral ears of said jaws, one of said connections being adjustable in respect of said carrier.

3. A work clamp for sewin machines comprising a carrier, independent clampjaws each provided at opposite ends with lat eral ears, and common adjustable pivotal connections intermediate said carrier and the lateral ears of said jaws.

4. A work clamp for sewin machines comprising a carrier, independent clampjaws each provided at opposite ends with lateral ears formed with stop-shoulders adapted to engage the other said jaw when the clamp is in inoperative position, and common pivotal connections intermediate said carrier and the lateral ears of said jaws.

5. A work clamp for sewing machines comprising a carrier, independent clampjaws each provided at opposite ends with lateral ears formed with stop-shoulders adapted to engage the other said jaw when the clamp is in inoperative position, common pivotal connections intermediate said carrier and the lateral ears of said jaws, and springs for normally pressing said jaws together with the stop-shoulders of the one in contact with the other.

6. A work clamp for sewing machines comprising a carrier, clamp-jaws each movable independently of the other, and common pivotal connections for said carrier and jaws disposed between the latter.

7. A work clamp for sewing machines comprising a carrier and clamp-jaws each movable independently of the other and provided at opposite ends with common pivotal connections for securing the same together and to said carrier, said connections being disposed intermediate the carrier and the operative portions of the clamp-jaws.

8. A work clamp for sewing machines comprising a pair of clamp-jaws each movable independently of the other, and a carrier therefor, lateral ears formed at opposite ends of each of said jaws, dependent lugs upon said carrier, and common pivotal pins each connecting together and to one of the dependent lugs of said carrier the lateral cars at corresponding ends of said aws.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

GEORGE S. GATCHELL.

Witnesses:

HENRY J. MILLER, H. C. KOMEMANN. 

